I've had the "Low Coolant" light on my 2001 Pontiac Grand Prix GTP flashing for a few weeks now. The coolant level was full and the temperature gauge never went past the 180 mark (the car has a 180 t- stat).
The problem was the coolant level sensor on the radiator. I took pictures of the process to access the sensor and created a quick guide.
Here's the page -
formatting link
You can either clean the sensor, replace it with a new one, or just disconnect it to eliminate the flashing "Low Coolant" light. Just be sure to keep an eye on the engine temps and check the coolant frequently if you disconnect the faulty sensor.Cheers, Paul